This invention relates to an improved battery operated burglar alarm in combination with a door chime adapted to a door or the like. Specifically, the device is an improvement in function and structure over my previously patented devices described in U.S. Pat. Nos. 4,123,752, 5,268,671 and RE 35,638. This device relates to an improvement in the sensing means with a simpler structure having fewer parts and easier assembly with increased reliability.
For example, the improvements in this invention to overcome the problems with the Novotny devices (U.S. Pat. No. RE 35,638, etc.) are explained as follows. The entire costly and unreliable mechanical sensing spring-activated plunger assembly (10, 12, 14) mounted to top cover (11), that requires direct contact with jamb plate (13) is eliminated including its cooperating make-break slide switch (15). Also, frictional wear caused by the rubbing action of plunger (12) against the bottom face of jamb plate (13) shortened the plunger (12) length after considerable use and affected the reliable triggering of break-make switch (15). In this invention, to overcome the above cost and wear problems, components, 10, 12, 14 of RE 35,638 are replaced by a permanent magnet (12) integrated into jamb plate (13) and a reed switch (14) mounted to printed circuit board (23) to achieve the combination of electrical logic functions required.
The costly 3-position instant lock-alarm slide switch (22) mounted to printed circuit board (23) is eliminated including the slide switch actuator (21) attached to slide (19). Misalignment mating problems between slide switch button (22A) with slide switch actuator (21) arose during the assembly of the front cover subassembly to the back plate (2). The cutout in slide switch actuator (21) must precisely engage slide switch button (22A) during assembly of the front cover subassembly to the back plate (2) to which the printed board circuit (23) and hence the 3-position instant lock-alarm slide switch (22) is already attached.
In this invention, to overcome the above misalignment assembly problem, the costly 3-position instant lock-alarm slide switch (20) and slide switch actuator (21) of U.S. Pat. No. RE 35,638 are replaced by a single bifurcated spring (22) attached to slide (19). The contact legs of bifurcated spring (22) automatically align themselves to mate with printed circuit board pads (10 and 10A) located on printed circuit board (23) as the front cover (11) is assembled to the back cover (2); the front cover (11) and back cover (2) each being part of front and back cover subassemblies respectively. This new structure prevents any final assembly misalignment problem between mating subassembly components during the final two subassemblies to form the final assembly of the Burglar Alarm and Door Chime.
This invention, like those of U.S. Pat. Nos. RE 35,638 and 5,268,671, includes the combination of instantaneous and simultaneous mechanical locking and alarm means for internal security and mode selection means for achieving the door chime mode or re-entry alarm delay mode. An optional smoke detector is also included. Further, detailed background information may be found in U.S. Pat. Nos. RE 35,638 and 5,268,671 and, for brevity, is not repeated here,. e.g.: reference to its use and advantages on doors in apartments, condos and single family homes.